Craigslist has been hugely popular among enthusiasts because it is easy to post and no signup is required (but is optional; I admit that I have an account). Furthermore, the postings are very clean and contain no ads. If you seek the something, you can search and hundreds of results will come up. The cloaking of your email address for your protection (if you opt-in) is also very desirable for those who hope to maintain their anonymity.